Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization.19. Synthesis and Characterization of Poly(2-(4-Biphenyloxy))ethyl Vinyl Etherby

摘要

The synthesis and living cationic polymerization of 2-(4-biphenyloxy)ethyl vinylether (BEVE) are described. Polymers with degrees of polymerization from 3.8 to 22.1 and narrow molecular weight distribution were synthesized and characterized by differential scanning calorometry (DSC) and thermal optical polarized microscopy. When determined from their first DSC heating scans poly(BEVE)s exhibit only a crystalline phase over the entire range of molecular weights. When determined from the second and first cooling scans, poly(BEVE) with a degree of polymerization of 3.8 exhibits an enantiotropic smectic mesophase and a crystallization process on the heating scan, while the polymers with degrees of polymerization from 4.7 to 8.1 exhibit only an enantiotropic smectic mesophase. The polymers with higher degrees of polymerization do not exhibit any mesophase. An explanation for this behavior is provided.